The disclosed embodiments relate to a medical device. Specifically, the disclosed embodiments relate to a catheter and a balloon catheter.
A conventional catheter is described in Japanese Patent Application Laid-Open No. 2012-100829. The catheter comprises an elongated tubular main body including an inner layer, a coil layer (a reinforcement body) formed with a wire material wound around the outer periphery of the inner layer, and an outer layer covering the coil body.
Further, Japanese Patent No. 3659664 describes a medical tube comprising an inner layer, a reinforcement layer adhered to the outside of the inner layer, and an outer layer adhered to the outside of the reinforcement layer. The reinforcement layer is a coil layer having a first coil and a second coil.
However, the catheter according to Japanese Patent Application Laid-Open No. 2012-100829 and the medical tube according to Japanese Patent No. 3659664 described above have the following problem: a reinforcement body formed of a coil tends to experience springback after bending, wherein the bend is partially released and an end of the coil “lifts” away from the inner layer.
Japanese Patent Application Laid-Open No. 2012-249812 attempts to solve the above problem. Japanese Patent Application Laid-Open No. 2012-249812 describes an outer catheter comprising an inner layer, an outer layer, and an intermediate layer (a reinforcement body) that is formed of a linear object and sandwiched between the inner layer and the outer layer, wherein a distal end of the intermediate layer is covered with a contrasting ring (a protective layer).
However, in the case of the outer catheter according to Japanese Patent Application Laid-Open No. 2012-249812, the outer diameter of the catheter is disadvantageously larger at the distal end of the intermediate layer because the contrasting ring is thick.